The giant table of road signs is a pictorial index to all the signs I have. The page contains about 1MB of images; so for representative samples check out:
You can download all 300+ road signs, in vector EPS and raster PNG format, as either one 9MB .zip file or one 8MB .tgz file. You can also download them in (uncompressed, patent-free) GIF format as one 3MB .zip file.
You can read a bit more about road signs and this project at my about road signs page.
The original EPS files of these road signs were extracted from the US Department of Transportation MUTCD (millenium edition). According to the MUTCD Introduction, "Any traffic control device design or application provision contained in this Manual shall be considered to be in the public domain. Traffic control devices contained in this Manual shall not be protected by a patent or copyright, except for the Interstate Shield." (The interstate shield is copyright AASHTO).
Because of this, I can hereby give away all these sign images to the public domain Non-License.